The overall objective of the proposed continuation project is to provide an understanding of the mechanisms of the foreign body reaction of tissue to implanted synthetic polymers. Our previous studies on the initial reactions of cells with foreign materials will be extended to the longer term, biologically functional events in the foreign body reactions. The cellular reactions occurring at the site of implantation at times ranging from the first few minutes up to several weeks strongly influence the long term acceptability of the implant. At present, the way these reactions differ on different materials is not well understood so that a rational choice of surgical implant materials with predictable in vivo response is not possible. The relation between these cellular responses and material properties therefore must be better understood. To achieve this goal, a set of three related objectives for this project have been chosen: 1) An examination of the organization of the adsorbed protein layer which forms on implanted materials is proposed, in order to understand how specific proteins in this layer involved in mediating cellular response to the material elicit different responses to different materials. 2) A set of materials designed to elicit changes in the organization of the adsorbed protein layer and subsequent cellular events will be prepared and characterized. The object of preparing these materials is to provide the basic means for perturbing the fundamental events in the foreign body reaction, and thus allow an approach to the mechanism of these events. 3) The reactions of macrophages, neutrophils and fibroblasts to this set of materials will be studied in order to determine how the material differences, propagated through an organizational influence on the adsorbed proteins, elicit differences in the foreign body reaction.